Estimates of worldwide oil in-place range up to 1.5 trillion barrels. Using that figure, since conventional recovery methods (primary and secondary) typically extract one-third of the original oil-in-place in a reservoir, it is estimated that the oil remaining as residual oil saturation after conventional recovery would be approximately 1.0 trillion barrels. Several enhanced oil recovery (EOR) techniques generally grouped together as tertiary production schemes have targeted this resource. In the past, chemical, thermal, and miscible techniques have been used by the industry. These EOR techniques typically involve injection of chemical compounds dissolved in water, the injection of steam, or the injection of a gas that is miscible with the oil in place.
The choice of EOR technique to be used is also dependent on other considerations such as depth, temperature, and amount of oil remaining in place. Much of the design phase of an EOR project is spent in the search for the combination of processes and injection schemes that will maximize oil recovery relative to the cost of implementing a particular technique. Most injection materials in use today have properties that differ considerably from the hydrocarbons in the reservoirs. Such differences in properties can reduce extraction efficiency.
Therefore there is a need for new and improved enhanced and/or improved oil recovery techniques.